Motion Tracking and Green Screen in AE CS3

[Dan Oster]

What’s the most effective way to achieve a garbage matte in AE? A mask with keyframes, right?

– Dan

[Chris Buttacoli]

Right. Very loose. I use about 8 points in my masks. Now, if the actor doesn’t move much you may not need to keyframe at all. But seeing as you will be zooming the camera, some mask animation is most likely needed.

[Dan Oster]

For the record, what is wrong with trying to key out bright orange or bright pink post-its (aka tracking points)?

– Dan

[Bill Morris]

It’s more work. If you garbage matte the post-its to match the green background, you then need only one key.

[Dan Oster]

Well I just show this piece on green screen with neon pink Post-Its as tracking points to compensate for the camera movement. In retrospect, I suppose I should have used a different shade of green for the markers as I am now having difficulty keying out the pink without screwing up peoples’ skin tone.

Is there a good way to do this? Or am I going to have to manually mask out these points (yikes)?

Here’s a rough example of the green screen plus pink tracking points: https://img411.imageshack.us/img411/861/greenscreenexample.jpg

Thanks for your help, guys!

– Dan

[Dan Oster]

show = shot

[Jim Dodson]

Hmmm… that’s an awful lot of tracking points…

What happened to the “two good points that never leave the frame idea??

Anyway,

You’ll want to use a separate application of “Keylight” just for the pink.

Color pick it — then change the “replace method” to “source” — (twirl down “screen matte” to find this menu option)…

If that doesn’t work — watch Ahron Rabinowitz’ “Super Tight Junk Mattes” —

https://library.creativecow.net/articles/rabinowitz_aharon/junk_mattes.php

Once you have a super tight junk matte — you can key out the trackers without influencing the actor(s)…. Or you may not even have to since you have super tight junk mattes….

Jim Dodson

8 Core Intel — Mac – OSX

[Dan Oster]

Hey, that works great! Particularly with judicious use of the “shrink/grow” option.

“What happened to the ‘two good points that never leave the frame idea??'”

Rest assured that advice was taken to the shoot. Most of these shots will be very tight, hence the many tracking points.

Thanks for the advice!

– Dan

[Dan Oster]

Here’s a photo from the shoot if people want a better point of reference.

https://img30.imageshack.us/img30/1641/bsgcastphoto.jpg

I’m still surprised there’s no easy way to key out those bright pink trackers. No way to lower the equivalent of the chroma key’s “tolerance”?

As always, thanks for the tips.

– Dan

[Jim Dodson]

Dan —

Using Keylight I was able to pull a seemingly toatally accedptable key…

I color picked the pink then twirled open “screen matte” and set clip black to 17.5 and clip white to 38.6

I think I was able to upload the matte here:
55_picture5.png.zip

Jim Dodson

8 Core Intel — Mac – OSX